Preheat the oven to 375°F (190°C).
Rinse and peel the sweet potatoes. Cut into 1-inch (2.5 cm) cubes. Toss with olive oil, salt, garlic powder, and cinnamon. Spread in a single layer on a rimmed baking sheet. Roast for 45 minutes, turning halfway through.
Cook the wild rice according to package instructions until tender. Drain if needed and season with salt. Set aside.
While the rice and sweet potatoes cook, prepare the dressing. Blend tahini, water, olive oil, garlic, parsley, basil, mint, honey, lemon juice, and salt until smooth. Add more water by the tablespoon if needed to thin.
Transfer the cooked rice to a large shallow serving dish. Layer arugula first, followed by roasted sweet potatoes, red onion, crumbled cheese, walnuts, and pomegranate seeds.
Just before serving, drizzle the tahini dressing over the salad. Serve cold or at room temperature. Toss with dressing immediately before eating for best texture.
Store leftovers in separate airtight containers in the refrigerator for up to 1 week.